#include <stdio.h>
#include <stdlib.h>

int cmp(const void*a,const void*b)
{
	return *(int*)b - *(int*)a;
}

int main()
{
	int i = 0;
	int line = 0;
	int arr[3] = {0};
	while(i<3)
	{
		scanf("%d",&line);
		arr[i] = line;
		i++;
	}
	qsort(arr,3,sizeof(arr[0]),cmp);
	if((arr[0] - arr[2]<arr[1])&&(arr[1]+arr[2]>arr[0]))
	    printf("yes");
	else
	    printf("no");
	
	return 0;
}
